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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.awt.image;

import java.awt.color.ICC_Profile;
import java.awt.geom.Rectangle2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.geom.Point2D;
import java.lang.annotation.Native;
import sun.awt.image.ImagingLib;

/**
 * This class implements a convolution from the source
 * to the destination.
 * Convolution using a convolution kernel is a spatial operation that
 * computes the output pixel from an input pixel by multiplying the kernel
 * with the surround of the input pixel.
 * This allows the output pixel to be affected by the immediate neighborhood
 * in a way that can be mathematically specified with a kernel.
 * <p>
 * This class operates with BufferedImage data in which color components are
 * premultiplied with the alpha component.  If the Source BufferedImage has
 * an alpha component, and the color components are not premultiplied with
 * the alpha component, then the data are premultiplied before being
 * convolved.  If the Destination has color components which are not
 * premultiplied, then alpha is divided out before storing into the
 * Destination (if alpha is 0, the color components are set to 0).  If the
 * Destination has no alpha component, then the resulting alpha is discarded
 * after first dividing it out of the color components.
 * <p>
 * Rasters are treated as having no alpha channel.  If the above treatment
 * of the alpha channel in BufferedImages is not desired, it may be avoided
 * by getting the Raster of a source BufferedImage and using the filter method
 * of this class which works with Rasters.
 * <p>
 * If a RenderingHints object is specified in the constructor, the
 * color rendering hint and the dithering hint may be used when color
 * conversion is required.
 * <p>
 * Note that the Source and the Destination may not be the same object.
 *
 * @see Kernel
 * @see java.awt.RenderingHints#KEY_COLOR_RENDERING
 * @see java.awt.RenderingHints#KEY_DITHERING
 */
public class ConvolveOp implements BufferedImageOp, RasterOp {

  Kernel kernel;
  int edgeHint;
  RenderingHints hints;
  /**
   * Edge condition constants.
   */

  /**
   * Pixels at the edge of the destination image are set to zero.  This
   * is the default.
   */

  @Native
  public static final int EDGE_ZERO_FILL = 0;

  /**
   * Pixels at the edge of the source image are copied to
   * the corresponding pixels in the destination without modification.
   */
  @Native
  public static final int EDGE_NO_OP = 1;

  /**
   * Constructs a ConvolveOp given a Kernel, an edge condition, and a
   * RenderingHints object (which may be null).
   *
   * @param kernel the specified <code>Kernel</code>
   * @param edgeCondition the specified edge condition
   * @param hints the specified <code>RenderingHints</code> object
   * @see Kernel
   * @see #EDGE_NO_OP
   * @see #EDGE_ZERO_FILL
   * @see java.awt.RenderingHints
   */
  public ConvolveOp(Kernel kernel, int edgeCondition, RenderingHints hints) {
    this.kernel = kernel;
    this.edgeHint = edgeCondition;
    this.hints = hints;
  }

  /**
   * Constructs a ConvolveOp given a Kernel.  The edge condition
   * will be EDGE_ZERO_FILL.
   *
   * @param kernel the specified <code>Kernel</code>
   * @see Kernel
   * @see #EDGE_ZERO_FILL
   */
  public ConvolveOp(Kernel kernel) {
    this.kernel = kernel;
    this.edgeHint = EDGE_ZERO_FILL;
  }

  /**
   * Returns the edge condition.
   *
   * @return the edge condition of this <code>ConvolveOp</code>.
   * @see #EDGE_NO_OP
   * @see #EDGE_ZERO_FILL
   */
  public int getEdgeCondition() {
    return edgeHint;
  }

  /**
   * Returns the Kernel.
   *
   * @return the <code>Kernel</code> of this <code>ConvolveOp</code>.
   */
  public final Kernel getKernel() {
    return (Kernel) kernel.clone();
  }

  /**
   * Performs a convolution on BufferedImages.  Each component of the
   * source image will be convolved (including the alpha component, if
   * present).
   * If the color model in the source image is not the same as that
   * in the destination image, the pixels will be converted
   * in the destination.  If the destination image is null,
   * a BufferedImage will be created with the source ColorModel.
   * The IllegalArgumentException may be thrown if the source is the
   * same as the destination.
   *
   * @param src the source <code>BufferedImage</code> to filter
   * @param dst the destination <code>BufferedImage</code> for the filtered <code>src</code>
   * @return the filtered <code>BufferedImage</code>
   * @throws NullPointerException if <code>src</code> is <code>null</code>
   * @throws IllegalArgumentException if <code>src</code> equals <code>dst</code>
   * @throws ImagingOpException if <code>src</code> cannot be filtered
   */
  public final BufferedImage filter(BufferedImage src, BufferedImage dst) {
    if (src == null) {
      throw new NullPointerException("src image is null");
    }
    if (src == dst) {
      throw new IllegalArgumentException("src image cannot be the " +
          "same as the dst image");
    }

    boolean needToConvert = false;
    ColorModel srcCM = src.getColorModel();
    ColorModel dstCM;
    BufferedImage origDst = dst;

    // Can't convolve an IndexColorModel.  Need to expand it
    if (srcCM instanceof IndexColorModel) {
      IndexColorModel icm = (IndexColorModel) srcCM;
      src = icm.convertToIntDiscrete(src.getRaster(), false);
      srcCM = src.getColorModel();
    }

    if (dst == null) {
      dst = createCompatibleDestImage(src, null);
      dstCM = srcCM;
      origDst = dst;
    } else {
      dstCM = dst.getColorModel();
      if (srcCM.getColorSpace().getType() !=
          dstCM.getColorSpace().getType()) {
        needToConvert = true;
        dst = createCompatibleDestImage(src, null);
        dstCM = dst.getColorModel();
      } else if (dstCM instanceof IndexColorModel) {
        dst = createCompatibleDestImage(src, null);
        dstCM = dst.getColorModel();
      }
    }

    if (ImagingLib.filter(this, src, dst) == null) {
      throw new ImagingOpException("Unable to convolve src image");
    }

    if (needToConvert) {
      ColorConvertOp ccop = new ColorConvertOp(hints);
      ccop.filter(dst, origDst);
    } else if (origDst != dst) {
      java.awt.Graphics2D g = origDst.createGraphics();
      try {
        g.drawImage(dst, 0, 0, null);
      } finally {
        g.dispose();
      }
    }

    return origDst;
  }

  /**
   * Performs a convolution on Rasters.  Each band of the source Raster
   * will be convolved.
   * The source and destination must have the same number of bands.
   * If the destination Raster is null, a new Raster will be created.
   * The IllegalArgumentException may be thrown if the source is
   * the same as the destination.
   *
   * @param src the source <code>Raster</code> to filter
   * @param dst the destination <code>WritableRaster</code> for the filtered <code>src</code>
   * @return the filtered <code>WritableRaster</code>
   * @throws NullPointerException if <code>src</code> is <code>null</code>
   * @throws ImagingOpException if <code>src</code> and <code>dst</code> do not have the same number
   * of bands
   * @throws ImagingOpException if <code>src</code> cannot be filtered
   * @throws IllegalArgumentException if <code>src</code> equals <code>dst</code>
   */
  public final WritableRaster filter(Raster src, WritableRaster dst) {
    if (dst == null) {
      dst = createCompatibleDestRaster(src);
    } else if (src == dst) {
      throw new IllegalArgumentException("src image cannot be the " +
          "same as the dst image");
    } else if (src.getNumBands() != dst.getNumBands()) {
      throw new ImagingOpException("Different number of bands in src " +
          " and dst Rasters");
    }

    if (ImagingLib.filter(this, src, dst) == null) {
      throw new ImagingOpException("Unable to convolve src image");
    }

    return dst;
  }

  /**
   * Creates a zeroed destination image with the correct size and number
   * of bands.  If destCM is null, an appropriate ColorModel will be used.
   *
   * @param src Source image for the filter operation.
   * @param destCM ColorModel of the destination.  Can be null.
   * @return a destination <code>BufferedImage</code> with the correct size and number of bands.
   */
  public BufferedImage createCompatibleDestImage(BufferedImage src,
      ColorModel destCM) {
    BufferedImage image;

    int w = src.getWidth();
    int h = src.getHeight();

    WritableRaster wr = null;

    if (destCM == null) {
      destCM = src.getColorModel();
      // Not much support for ICM
      if (destCM instanceof IndexColorModel) {
        destCM = ColorModel.getRGBdefault();
      } else {
                /* Create destination image as similar to the source
                 *  as it possible...
                 */
        wr = src.getData().createCompatibleWritableRaster(w, h);
      }
    }

    if (wr == null) {
            /* This is the case when destination color model
             * was explicitly specified (and it may be not compatible
             * with source raster structure) or source is indexed image.
             * We should use destination color model to create compatible
             * destination raster here.
             */
      wr = destCM.createCompatibleWritableRaster(w, h);
    }

    image = new BufferedImage(destCM, wr,
        destCM.isAlphaPremultiplied(), null);

    return image;
  }

  /**
   * Creates a zeroed destination Raster with the correct size and number
   * of bands, given this source.
   */
  public WritableRaster createCompatibleDestRaster(Raster src) {
    return src.createCompatibleWritableRaster();
  }

  /**
   * Returns the bounding box of the filtered destination image.  Since
   * this is not a geometric operation, the bounding box does not
   * change.
   */
  public final Rectangle2D getBounds2D(BufferedImage src) {
    return getBounds2D(src.getRaster());
  }

  /**
   * Returns the bounding box of the filtered destination Raster.  Since
   * this is not a geometric operation, the bounding box does not
   * change.
   */
  public final Rectangle2D getBounds2D(Raster src) {
    return src.getBounds();
  }

  /**
   * Returns the location of the destination point given a
   * point in the source.  If dstPt is non-null, it will
   * be used to hold the return value.  Since this is not a geometric
   * operation, the srcPt will equal the dstPt.
   */
  public final Point2D getPoint2D(Point2D srcPt, Point2D dstPt) {
    if (dstPt == null) {
      dstPt = new Point2D.Float();
    }
    dstPt.setLocation(srcPt.getX(), srcPt.getY());

    return dstPt;
  }

  /**
   * Returns the rendering hints for this op.
   */
  public final RenderingHints getRenderingHints() {
    return hints;
  }
}
